This invention relates generally to transferring electrical power in an aircraft, more particularly to transferring power between an energy storage device in an electrical accumulator unit (EAU) and an electrical power system
Conventional aircraft power systems that provide power to electrical aircraft loads can suffer from a variety of deficiencies. For example, conventional aircraft power systems require the use of generators to produce power for an aircraft. These generators may be required to supply a very large amount of power over a short duration during a spike when a large surge of power is needed. For example, on average, an aircraft power system may draw about 60 kilowatts of power from a generator, but there may be times when the power system requires 130 kilowatts of power from the generator for a short period of time. Therefore, in order for a generator to be able to handle this large spike in power needed, conventional power systems require generators with a high rating. Unfortunately, generators with a high rating are not only more expensive than lower rated generators, they are also larger and heavier.
Some of the latest aircraft power systems also include electrical actuator loads for moving, for example, a surface of a plane such as a rudder. The use of electrical actuators on aircraft is expected to become more and more common in future aircraft designs. When an actuator motor is instructed to stop, the motor is de-accelerated. The de-acceleration of an actuator generates kinetic energy which is converted to electrical energy by the actuator and placed back onto the power system and therefore back to a generator. The resulting electrical power from this recovered kinetic energy is called regenerated power. Thus, because a generator cannot absorb this power, resisters are utilized to dissipate the kinetic energy that is returned from the actuator after de-acceleration. This creates heat, and because this heat is not utilized, the heat created by the resisters may cause problems with a cooling system on an aircraft.
Conventional aircraft power systems also include two battery supplies. One battery (e.g., a primary battery) acting as a primary energy storage device to an engine controller and a secondary battery acting as a backup to the primary battery. Thus, in an event of a failure or drainage of the primary battery, an engine controller draws power from the secondary battery to continue operation. However, the use of two batteries as part of a redundant system not only increases the overall weight of an aircraft, but can reduce the ability of the aircraft to carry additional payload.